Magellan GPS 2000

...boat handling.

Magellan GPS 2000 - a solution?

Yes – one of them. Never a substitute for accurate chartwork, DR navigation and log-keeping. There are other ways of finding out position like Decca (Europe) and Loran (in the US), but both these methods, based on radio beacons have built-in errors and still require some adjustment. Satellite navigators like GPS 2000 used to have built-in errors for US defence considerations, ...
...that more modern sets from Magellan and others will be somewhat neater than this and weigh less.

Cost

At Christmas 1997 it cost £180 and was discounted. Now I see that comparable or better sets are selling for about £100-£120. See the Magellan website for an update (go to
http://www.magellangps.com or use search engines for your country’s supplier. If $US are quoted, rule of thumb is £ in the UK (that’s ... more

This is a great sat-nav instrument for anyone who has ever stood in remote country staring at an Ordnance Survey map, compass in hand, gazing at scenery that looks the same no matter which direction you inspect it from. Or, peering through a suddenly-descending mist at sea wondering where the harbour channel is, with the depth-sounder rapidly registering shallow water.

I confess – I have been there. As a keen hill-walker my usual haunts are in the Scottish Highlands and as a sail cruiser skipper I have sailed off the West Coast of Scotland.

Hill-walking

Normally a map and compass and training in how to use them are all that’s needed to navigate around the hills in safety. Careful attention to detail and logging your observed position every half hour or so helps when conditions deteriorate and heavy rain starts or a hill fog descends. In 99% of situations I have been in this is perfectly adequate and for the other 1% when the forecast was particularly inaccurate you can adopt sensible strategies such as steering an escape course by which you know you can avoid major hazards (e.g. cliffs) and eventually reach safety. But there are times when you just feel you could do with a precision plot on that map – a nice pencilled ‘X’ saying ‘you are definitely here!’

Sailing

Same thing, but there is the added dimension of water depth and usually several crew to be concerned about from the safety angle. Again chart and compass work with depth sounder (if working!) and log (naval speedo) can give a so-called dead reckoning (DR) position, with adjustments for tidal drift and leeway for wind conditions. There is some element of guesswork and estimation in this and in poor conditions, updating the chart can be difficult and especially so if the crew is inexperienced at boat handling.

Magellan GPS 2000 - a solution?

Yes – one of them. Never a substitute for accurate chartwork, DR navigation and log-keeping. There are other ways of finding out position like Decca (Europe) and Loran (in the US), but both these methods, based on radio beacons have built-in errors and still require some adjustment. Satellite navigators like GPS 2000 used to have built-in errors for US defence considerations, but in August 2000 these were removed and the accuracy of readings improved from around 10-100metres down to what is now about 1-3 metres from my observations.

Position co-ordinate systems

There are quite a few alternatives provided as standard – Ordnance Survey co-ordinates (land use), Latitude/Longitude (sea and air) are two major ones. OS readings are given to the usual sheet and 6-figure reference on the chart which is actually less accurate than the GPS can give you. (Each figure representing a 10 metre distance on the OS map).

Features

There are so many features provided with this (now ageing!) set that I can only mention the main ones – ones I find useful. A comprehensive manual is provided with the set.

Precision position read-out. This is the top priority for me – it tells me precisely where I am (that ‘X’ on the map).

Height – because the satellites can compare their relative height above the Earth, one’s own position in relation to mean sea level can be calculated with some precision. This also helps to confirm the exact position (provided enough satellites are ‘locked’ on). Looking at the ‘X’ on the chart is the contour height consistent with the height reading?

Set ‘waypoints’ and the GPS set tells you how far to go and in what direction. It can also show you graphically which way to point the set and that is the direction to go in. The set also advises you if you are running off-track and the bearing to take to get back on. On certain displays it can provide a running commentary on your speed and time to your destination. Not many trains manage this in the UK, perhaps it could be fitted to them.

‘Backtrack’ facility allows you to steer back exactly the way you came – this is especially important when conditions make visibility very poor and you want to avoid the cliff falling-off routine very badly! Or just to get back, period.

Other general features are that it is tough, waterproof, the display is scratch resistant, has useful set-up menus (if you tell it approximately where you are this speeds up its position finding) and batteries last for 24 hours continuous use. A backlight permits use at night. Its size is marginally bigger than a mobile phone (16.7cm x 5.8 cm x 3.3 cm) and it weighs just a little more at 10oz (283 grams). Note that more modern sets from Magellan and others will be somewhat neater than this and weigh less.

Cost

At Christmas 1997 it cost £180 and was discounted. Now I see that comparable or better sets are selling for about £100-£120. See the Magellan website for an update (go to
http://www.magellangps.com or use search engines for your country’s supplier. If $US are quoted, rule of thumb is £ in the UK (that’s another story). It’s not necessary to buy the most expensive set – just get the one that does the basics well and suits your purposes.

The Test Drive

2 examples will do, otherwise Ciao! will start charging me for disk space.

1. Bishop Hill, Kinross, Fife (East Scotland).
Following an OS/Jarrold guide with a 2.5 in to 1 mile inset map, I climbed this hill. On the way up I checked my position visually on the map. This was not easy since a fairly dense hill fog had come down, but at least there features like walls and fields which were recognisable. I checked the position with the GPS which suggested I was about 1km further North than I thought. It can’t be that inaccurate surely? Maybe it was the fog causing some electrical confusion in its circuits. Then the thought occurred to me that the map might be wrong, because one of them had to be. I continued carefully with more visual checks that I could make and finished the walk. When I got home and checked the main 1.25 in OS map –sure enough the co-ordinates on my walk guide map were one square (i.e. 1 kilometre) out. This meant that the map was showing my position 1 km too far South compared to where I really was. An interesting one. The publisher (Jarrold) acknowledged this was correct and built this in to their next edition.

2. Cairn Mairg range – Glen Lyon (Highlands).

I had completed 2 of the 4 ‘Munros’ in this range (3000 foot plus from a selected list of Scottish mountains) and was on the 3rd when the cloud came down over its top. Accompanying the cloud was fairly monsoon-like conditions. I discovered a poor fellow traveller at the top. ‘Are you going on to the next one then?’, I asked, thinking at least we’d be in the same boat. ‘No bloody chance, I’m off down the glen to the nearest bothy for shelter’, he groused from under his sodden anorak hood. ‘OK, then I’m pushing on – see you’. I left the top clambering over a boulder field like something out of a bizarre ancient building site and got to the ridge which would take me to the final Munro. I bashed on, climbing up to the top in visibility down to 10 metres.

When I got there (it was obviously the top because the land fell away all around!), the terrain was smooth and grassy and not at all as advertised (‘a rocky spur marks the top’ said the guide book). Out came the map and the Magellan. I had climbed to the wrong ‘top’. Using my compass to steer based on the GPS position, I got back to the correct place on the ridge and suddenly the clouds lifted. Like something from a movie set literally hundreds of red deer were moving on the hillside below more or less the way I had come, so I stood still for several minutes, half expecting Rob Roy to turn up, until they passed and made my way up to the correct summit.

Conclusion

This is the ultimate outdoor sport ‘toy’ but it can seriously help you out of a jam when ‘lost’ and at the very least save valuable time spent hunting for the right track. I also use it to confirm position under normal conditions. On rarer (I sincerely hope) occasions it can save lives if, despite all sensible hillcraft precautions having been taken, one is lost for whatever reason. In event of injury and a mobile phone has reception, the precise position of the party can be taken by the emergency services and save possibly hours of fruitless searching and potential loss of life due to delay.

At sea, the benefits are equally obvious and it gives all small craft a decided advantage in position fixing when other means cannot be used due to poor visibility or other equipment has broken down. The cost in relation to possible benefits is, in my view a small one to pay.
 

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